A vehicle includes a rocker assembly. The rocker assembly is typically the lowest portion of a side of a body of the vehicle between tires of the vehicle. The rocker assembly extends along a vehicle-longitudinal axis. The rocker assembly may support a door of the vehicle in a closed position. The rocker assembly may include a step to ease entry and egress to and from the vehicle. The rocker assembly may deform upon application of sufficient force, e.g., during a vehicle side impact.